Use of electronic descaling technology to control precipitation fouling in plate-and-frame heat exchangers

The objective of the present paper was to investigate the validity of the electronic descaling (ED) technology through accelerated fouling tests. A small plate-and-frame heat exchanger (with 20 stainless steel plates) was used for the tests, where pressure drop and overall heat transfer coefficients were measured over a range of flow rate. In order to accelerate the rate of fouling in a laboratory test, artificial hard water of 1,000 ppm as CaCO3 was recirculated at relatively small flow rates. The 1,000 ppm hard water was prepared by adding CaCl2 (0.01 M) and NaHCO3 (0.02 M) to tap water. The test results depicted that the ED technology could significantly reduce new scale deposits even in the accelerated fouling test, which had an extremely harsh fouling environment. A field test with a much larger plate-and-frame heat exchanger (with 140 titanium plates) demonstrated that the ED technology could keep plate surfaces scale-free, maintaining the initial heat transfer coefficient indefinitely.